51644 ÷ 8 = 6455 R4
Let's divide 51644 by 8.

Step 1:
8 goes into 5 0 times with a remainder of 5.
Write down 0 as next digit of of the result. 
Result so far: 0
Subtract 0 from 5 to get 5.
Bring next digit (1) of the dividend behind the 5 and repeat the process: 51 / 8

Step 2:
8 goes into 51 6 times with a remainder of 3.
Write down 6 as next digit of of the result. 
Result so far: 6
Subtract 48 from 51 to get 3.
Bring next digit (6) of the dividend behind the 3 and repeat the process: 36 / 8

Step 3:
8 goes into 36 4 times with a remainder of 4.
Write down 4 as next digit of of the result. 
Result so far: 64
Subtract 32 from 36 to get 4.
Bring next digit (4) of the dividend behind the 4 and repeat the process: 44 / 8

Step 4:
8 goes into 44 5 times with a remainder of 4.
Write down 5 as next digit of of the result. 
Result so far: 645
Subtract 40 from 44 to get 4.
Bring next digit (4) of the dividend behind the 4 and repeat the process: 44 / 8

Step 5:
8 goes into 44 5 times with a remainder of 4.
Write down 5 as next digit of of the result. 
Result so far: 6455
Subtract 40 from 44 to get 4.

The final result is 6455 with a remainder of 4.